Generally, a device is provided with a casing which covers a module thereinside. Such a casing that covers the inside of the device may be called a case, a cover, a cabinet, an enclosure, a package, housing, a box, etc. according to the kind of the device. The casing has high mechanical strength and protects a module inside the device. Therefore, when a worker covers the module in a device with a casing in order to assemble the device, the casing may contact the module and damage the module. Accordingly, the device needs a mechanism to prevent such damage. A case in which the above-mentioned problem may occur is described below using a liquid crystal display (LCD) device as a specific example.
An LCD device includes features like a thin shape, a light weight, and low power consumption, and is used in wide range of fields, such as office automation (OA) equipment, audiovisual (AV) equipment, and portable terminal equipment. For example, the LCD device includes an LCD panel, a backlight, a circuit element and an outside casing, as main components. The liquid crystal panel includes two substrates facing each other and liquid crystal sandwiched therebetween. The backlight includes a light source, optical members such as a reflecting sheet and a diffusion sheet, an inside resin casing which holds and fixes above mentioned parts. The circuit element includes a driver chip for driving the LCD panel, a driving circuit substrate and the like. The outside casing is made of a hard material, such as a metal, which holds and fixes the LCD panel, the backlight, the circuit element, etc.
The driving circuit substrate is installed in a rear face of the backlight. The liquid crystal panel and the driving circuit substrate are connected to each other via a substrate in which conductive wirings, such as a copper foil, are formed on a flexible resin film of a polyimide etc. Hereafter, such a substrate having flexibility is called a “flexible substrate”. The driver chip is mounted on the flexible substrate. Such structure of a flexible substrate is disclosed in Japanese Patent Application Laid-Open No. 2006-100664 (patent document 1).
Including a resin film as a base material, a flexible substrate is susceptible to being damaged. A driver chip is readily affected by impact, vibration, and the like. Therefore, in the LCD device of the patent document 1, a space is usually made between the inside casing and the outside casing of the LCD device. The space is located on the side face of the LCD panel and the backlight. The flexible substrate and the driver chip on it are housed in the space, and do not have contact with the adjacent structural members, in particular, the outside casing made of a hard material, such as a metal.
A recent LCD device is required to narrow the bezel (outside margin around the display screen). Thus, it is difficult to secure enough space near the side face of the LCD panel and the backlight. Therefore, the flexible substrate or the driver chip may have contact with the outside casing during assembly of the LCD device. Then, defects, such as breaking of the trace on the flexible substrate or damage of the driver chip occur.
FIGS. 17 and 18 are cross sectional views showing structures of the LCD device of Japanese Patent Application Laid-Open No. 2003-167230 (patent document 2). In the LCD device of the patent document 2, as shown in FIG. 17, a protective cover 25 is arranged on the inner surface of an outside casing (bezel 24). A first fixing part 25a of the protective cover 25 is fixed to the inner surface of a pendent part 24a of the bezel 24, and a second fixing part 25c is fixed to the back of an inside casing (plastic chassis 27). A non-fixing part 25b between the first fixing part 25a and the second fixing part 25c protects a TAB (tape automated bonding) substrate 23 and an IC chip 23a such as a driver chip. A TAB substrate is a flexible wiring substrate having TAB.
As shown in FIG. 18, which shows another structure of the LCD device of the patent document 2, the inner surface and the external surface of the edge of the pendent part 24a of the bezel 24 are covered with a masking tape 26. In such structure, the TAB substrate 23 and the IC chip 23a do not directly touch the pendent part 24a of the bezel 24.